Direct observation of distorted wave effects in ethylene using the (e,2e) reaction

Area of Science:

• Quantum mechanics
• Molecular physics
• Electron spectroscopy

Background:

• Electron momentum distributions provide insights into molecular electronic structure.
• The (electron, 2 electron) or (e,2e) reaction is a powerful tool for probing electron behavior in atoms and molecules.
• Previous studies often relied on simplified theoretical approximations like the plane-wave impulse approximation.

Purpose of the Study:

• To directly measure electron momentum distributions for ethylene.
• To investigate the influence of impact energy on (e,2e) cross-section discrepancies.
• To explore the role of distorted-wave effects in molecular electron dynamics.

Main Methods:

• Utilized the (e,2e) reaction technique for electron momentum mapping.
• Conducted experiments with ethylene at varying impact energies (400–2400 eV).
• Compared experimental results with plane-wave impulse approximation calculations.

Main Results:

• Observed "turn up" effects in the (e,2e) cross sections for the 1b(3g) orbital at low and high momentum regions.
• Noted that these discrepancies decreased with increasing impact electron energies.
• Identified a correlation between experimental observations and the predicted influence of distorted-wave effects.

Conclusions:

• The observed discrepancies in ethylene's electron momentum distributions are attributed to distorted-wave effects.
• Current theoretical models struggle to accurately incorporate these distorted-wave effects in molecular systems.
• Further development of theoretical frameworks is needed for precise electron dynamics calculations in molecules.